The restraint system of this invention includes a known restraint module having a support, an enclosure mounted on the support, a folded occupant restraint cushion mounted on the support and housed within the enclosure, and a gas generator or source of pressure fluid which is mounted on the support and communicates with the interior of the folded cushion. The cushion may be folded as shown in co-pending application Ser. No. 270,609, Cok et al., Modular Occupant Restraint System, filed Nov. 14, 1988, now U.S. Pat. No. 4,903,986, and assigned to the assignee of this invention.
In accordance with this invention, a planar band of steel wraps around the folded cushion. The band extends from one edge portion of the support to the other like edge portion thereof over the folded wall portions of the cushion corresponding to such edge portions and the upper wall portion of the cushion. The band includes tapered portions which are asymmetrically arranged with respect to each other and have their apical portions joined across a narrow width juncture or portion which is located approximately midway between the like wall portions of the cushion. During the initial deployment of the cushion, the band prevents the upper wall portion from deploying normal to or toward the occupant and instead forces the cushion to bulge or deploy laterally or generally parallel to the occupant. When the cushion attains a predetermined internal pressure, the cushion ruptures the band at the narrow width portion and then deploys normal to or toward the occupant. The band preferably extends between the longer or 3 and 9 o'clock side edge portions of the support over the fan folded side wall portions of the cushion. The band may also extend between the shorter 6 and 12 o'clock end edge portions of the support over the pleat folded end wall portions of the cushion.
The primary feature of this invention is that it provides an occupant restraint system which releasably retains an inflatable occupant restraint system against deployment normal to or toward the occupant during the initial inflation of the cushion from a source of pressure fluid. Another feature is that the cushion is held against deployment by a planar band which wraps over folded side wall portions and the upper wall portion of the cushion. A further feature is that the band has a weakened portion which ruptures when the internal pressure of the cushion exceeds a predetermined limit to thereby permit deployment of the cushion normal to or toward the occupant. Yet, another feature is that the band is of steel and includes end portions secured to the support to which the cushion is mounted and asymmetrically arranged tapered portions which are joined at their narrow width apical ends to provide the weakened portion.